Apparatus for supporting electric-component mounter

ABSTRACT

An apparatus for supporting an electric-component mounter including a substrate supporting device which supports a circuit substrate, an electric-component supplying device which supplies a plurality of electric components to be mounted on the circuit substrate, a mounting device which receives the electric components from the electric-component supplying device and mounts the electric components on the circuit substrate supported by the substrate supporting device, and a base member which supports the substrate supporting device, the electric-component supplying device, and the mounting device, the apparatus including at least one elastic member which is provided between the base member and a surface of a floor which supports the base member, and at least one damper which damps vibration of the base member and the floor surface relative to each other, the vibration resulting from elastic deformation of the elastic member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for supporting anelectric-component mounter and particularly to the art of reducing thevibration of a floor which supports the electric-component mounter.

2. Related Art Statement

There is known an electric-component ("EC") mounter which includes acircuit-substrate ("CS") supporting device, an EC supplying device, andan EC mounting device. Those devices are supported on a common basemember which is provided on the surface of a floor. The EC mountingdevice receives, from the EC supplying device, ECs (e.g., electroniccomponents) as elements of an electric circuit (e.g., an electroniccircuit), and mounts the ECs on a CS (e.g., a printed circuit board)supported by the CS supporting device. In this sort of EC mounter, atleast one of the EC mounting device, the CS supporting device, and theEC supplying device includes a movable member which is movable fortransferring the ECs supplied from the EC supplying device or mountingthe ECs on the CS. Therefore, when the ECs are mounted on the CS, themovable member is accelerated and decelerated and accordingly the basemember is subjected to vibration. Since the base member is fixedlysupported by the floor, almost all the vibrational energy is transmittedto the floor. Thus, not only the base member but also the floor arevibrated. The base member may be fixedly supported by the floor, in sucha manner that the floor surface is covered with a leveling sheet formedof steel and the base member is placed on the leveling sheet via aplurality of leveling bolts. In this manner, the level at which the CSis conveyed, and the level at which the EC mounting device and the ECsupplying device are provided, can be adjusted. In addition, theplurality of leveling bolts can be contacted with the floor surface at asubstantially uniform pressure. Thus, the base member and the floor areconnected to each other as if it were a unit. Thus, almost all thevibrational energy is transmitted to the floor.

If a rubber sheet is inserted between the leveling sheet and the floor,the vibrational energy which is transmitted to the floor can be more orless reduced by the elastic deformation of the rubber sheet. However,this reduction is not satisfactory. In a particular case, the frequencyof the vibration exerted to the rubber sheet coincides with the naturalfrequency of the same. In this case, the rubber sheet resonates and thevibration is amplified.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide anelectric-component-mounter supporting apparatus which reduces thevibration of a floor resulting from the vibration of anelectric-component mounter.

The present invention provides an electric-component-mounter supportingapparatus which has one or more of the technical features that aredescribed below in respective paragraphs given parenthesized sequentialnumbers (1) to (15). Any technical feature which includes anothertechnical feature shall do so by referring, at the beginning, to theparenthesized sequential number given to that feature. Thus, two or moreof the following technical features may be combined, if appropriate.Each technical feature may be accompanied by a supplemental explanation,as needed. However, the following technical features and the appropriatecombinations thereof are just examples to which the scope of the presentinvention is by no means limited.

(1) According to a first feature of the present invention, there isprovided an apparatus for supporting an electric-component mounterincluding a substrate supporting device which supports a circuitsubstrate, an electric-component supplying device which supplies aplurality of electric components to be mounted on the circuit substrate,a mounting device which receives the electric components from theelectric-component supplying device and mounts the electric componentson the circuit substrate supported by the substrate supporting device,and a base member which supports the substrate supporting device, theelectric-component supplying device, and the mounting device, theapparatus comprising at least one elastic member which is providedbetween the base member and a surface of a floor which supports the basemember; and at least one damper which damps vibration of the base memberand the floor surface relative to each other, the vibration resultingfrom elastic deformation of the elastic member. The mounting device maybe one which includes a plurality of electric-component ("EC") holderswhich are revolveable around a common axis; and an EC-holder positioningdevice which sequentially positions the EC holders at at least onepredetermined operation position on the locus of revolution of the ECholders. The at least one operation position may include an EC-receiveposition where the mounting device receives the ECs from the ECsupplying device. The EC-holder positioning device may be one whichincludes a plurality of rotary members which are rotatable about theabove-indicated axis line, independent of each other, and which supportthe plurality of EC holders, respectively, at respective equal radialdistances from the common axis; and a rotary-motion applying devicewhich applies a rotary motion to each of the rotary members such thateach of the rotary members is fully rotated by 360 degrees about thecommon axis while being stopped at least one time during its fullrotation and having a predetermined time difference from each of itspreceding and following rotary members. Otherwise, the EC-holderpositioning device may be one which includes an intermittent-rotationbody which is intermittently rotatable about the above-indicated commonaxis and which supports the plurality of EC holders at respective equalradial distances from the common axis; and a rotating device whichintermittently rotates the intermittent-rotation body at the sameangular pitch as that at which the EC holders are equiangularly spacedfrom each other about the common axis. The intermittent-rotation bodywhich is rotated while supporting the EC holders may be replaced with arotatable body which is rotatable by any desired angle in each ofopposite directions. The mounting device may be one which includes atleast one EC holder; and a movable member which supports the at leastone EC holder and which is linearly movable in at least one of twodirections perpendicular to each other on a plane. The mounting devicemay be one which is disclosed in U.S. patent application Ser. No.08/977,662 assigned to the Assignee of the present application, i.e. onewhich includes a plurality of EC holders; the above-indicated, secondEC-holder positioning device; and a movable member which supports the ECholders and the EC-holder positioning device and which is linearlymovable in at least one of two directions perpendicular to each other ona plane. The substrate supporting device may be selected from varioussorts of devices such as a device which supports and moves the circuitsubstrate, or a device which positions and supports the circuitsubstrate but does not move the same. The EC supplying device may beselected from various sorts of devices such as a movable device whichstores the ECs and is movable, or a stationary device which stores theECs but is not movable. Even if the EC mounter may vibrate when mountingthe ECs on the circuit substrate, the elastic deformation of the elasticmember permits the base member to move relative to the floor surface, sothat the vibration of the EC mounter is prevented from being transmittedto the floor. In addition, the damper damps the relative vibration ofthe base member and the floor. Since the damper is provided between thebase member and the floor, a portion of the vibration of the base memberis damped by the damper whereas another portion of the vibration istransmitted to the floor via the damper. However, this portion is muchsmaller than the vibration which is transmitted to the floor in the casewhere neither the elastic member nor the damper is provided. Thus, thevibration of the floor is largely reduced, and the vibration of the basemember is prevented from lasting for a long time, or being amplifiedbecause of resonance. The present apparatus can largely reduce thevibrational energy transmitted to the floor, than a conventionalarrangement wherein a rubber sheet is inserted between a levelling sheetand a floor. That is, the present apparatus prevents the vibration ofthe floor, thereby preventing the vibration of other devices provided onthe floor surface, the generation of noise, and the deterioration oflife expectancy of the building in which the EC mounter is disposed. Inaddition, the present supporting apparatus damps the vibration of thebase member, thereby reducing the amplitude of the vibration of the ECmounter. Therefore, for example, the substrate supporting device canreliably receive and pass the circuit substrate from and to the otherdevices, because the substrate supporting device is not so largelydislocated relative to the other devices. The elastic member may beprovided by a coil spring that is elastically deformable in a directionparallel to its center axis line and directions perpendicular to thecenter axis line. In the case where the coil spring is disposed suchthat the center axis line of the coil spring extends perpendicularly tothe floor surface, the coil spring can permit the relative vibration ofthe base member and the floor in all directions.

(2) According to a second feature of the present invention that includesthe first feature (1), the mounter supporting apparatus furthercomprises at least one upper member which is fixed to the base member;and at least one lower member which is provided on the floor surface,the elastic member and the damper being provided between the upper andlower members. The elastic member may be provided between a first pairof upper and lower members, and the damper may be provided between adifferent, second pair of upper and lower members. According to thesecond feature, however, the elastic member and the damper are providedbetween the common pair of upper and lower members, so that the elasticmember and the damper are connected to each other. Consequently theelastic deformation of the elastic member is effectively reduced by thedamper, so that the relative vibration of the base member and the flooris effectively damped. In addition, according to this feature, thesupporting apparatus including the elastic member and the damper can beproduced and handled as a unit, which facilitates disposing the ECmounter on the floor. Though the upper member needs to be substantiallyfixed to the base member such that the upper member is not movablerelative to the same, it need not be fixed using a fixing member ordevice such as bolts.

(3) According to a third feature of the present invention that includesthe first or second feature (1) or (2), the mounting device receives, ata predetermined component-receive position, the electric components fromthe electric-component supplying device, and the electric-componentsupplying device comprises a movable electric-component supplying devicewhich includes a movable table which is movable along a straight linepassing through the component-receive position; and a plurality ofcomponent supplying units which are provided on the movable table andeach of which is selectively positioned at the component-receiveposition by the movement of the movable table, and the damper damps therelative vibration of the base member and the floor surface in at leasta direction parallel to the straight line. Each of the componentsupplying units may be one which includes an EC-supply portion and atape feeding device which feeds an EC carrier tape including an ECaccommodating tape accommodating the ECs, such that the ECs are fed oneby one to the EC-supply portion; or otherwise one which includes anEC-supply portion and utilizes vibration, inclination, air flow, one ormore conveyor belts, or the combination of two or more of them, forfeeding the ECs in an array, such that the ECs are fed one by one to theEC-supply portion. In either case, each component supplying unit mayfurther include an EC storing device which stores the ECs or the ECcarrier tape; and a main frame. The main frame may, nor may not, supportboth the EC feeding device and the EC storing device. In the case wherethe main frame supports both the EC feeding device and the EC storingdevice, the main frame is attached to the movable table, whereby boththe EC feeding device and the EC storing device are moved with themovable table. In the case where the main frame supports the EC feedingdevice but does not support the EC storing device, the main frame isattached to the movable table, whereby only the EC feeding device ismoved with the movable table. In the latter case, the respective ECstoring devices of the component supplying units may be provided onanother movable table, or may be provided on a stationary table, i.e.,may be fixed in position. Since the movable table on which the pluralityof component supplying units are provided has a great mass, the basemember is subjected, when the movement of the table is started or ended,to a great vibrational force in a direction parallel to the direction ofmovement of the table, so that the base member is vibrated in thatdirection. According to this feature, the damper effectively damps thevibration of the base member produced in the very direction. Thelinearly movable table may be replaced with a table which is movablealong a line other than the straight line, for example, a circle, acircular arc (i.e. a part circle), a curve other than the circular arc,or a single line obtained by combining two or more of them. In the caseof the circle, the linearly movable table may be replaced with acircular (i.e., full-circular) table which is rotatable about an axisline. In the case of the circular arc, the linearly movable table may bereplaced with a sectorial table which is rotatable about an axis line.Each of the circular and sectorial tables can be said as a rotary tablewhich is rotatable about an axis line. Also in the case where thelinearly movable table is replaced with the rotary table, the elasticdeformation of the elastic member permits the relative vibration of thebase member and the floor and the damper damps the relative vibration.However, generally, the vibration of the base member produced in thecase where the linearly movable table is started and stopped is muchgreater than that produced in the case where the rotary table is startedand stopped. Thus, the present supporting apparatus is more advantageouswhen used with the linearly movable table than when used with the rotarytable.

(4) According to a fourth feature of the present invention that includesthe third feature (3), the damper damps the relative vibration of thebase member and the floor surface in all directions on at least avertical plane parallel to the straight line. As described above, whenthe linearly movable table is started and stopped, the base member issubjected to a great vibrational force in a direction parallel to thedirection of movement of the table. Generally, the level or heightposition at which the vibrational force is applied to the base member isdifferent from that at which the base member is supported by the mountersupporting apparatus. Therefore, the base member is subjected to amoment and accordingly a rotational vibration. Consequently a portion ofthe base member that is supported by the supporting apparatus issubjected to the vibration including all components corresponding to alldirections on a vertical plane parallel to the direction of movement ofthe table. According to this feature, the damper damps the vibrationproduced in all the directions on the vertical plane. Thus, the presentsupporting apparatus effectively damps the vibration of the base member.In the case where the damper can additionally damp the vibrationproduced in a direction perpendicular to the direction of movement ofthe table on a plane parallel to the floor surface, the presentapparatus can more effectively reduce the vibration of the base member.

(5) According to a fifth feature of the present invention that includesany one of the first to fourth features (1) to (4), the damper comprisesan adjustable damper which has an adjustable vibration dampingcharacteristic. The amplitude of the vibration of the floor resultingfrom the vibration transmitted thereto from the base member, changesdepending upon the conditions of the floor, such as its rigidity, mass,and vibration damping characteristic. According to the fifth feature,the mounter supporting apparatus includes the adjustable damper whosevibration damping characteristic is adjustable. For example, when the ECmounter is disposed on the floor, the vibration damping characteristicof the damper is adjustable depending upon the conditions of the floor,so that the amplitude of vibration of the floor is minimized. Theamplitude and frequency of the vibration transmitted from the basemember to the floor change depending upon the conditions of the ECmounter, such as its mass and the speed of movement of its movablemember or members. The mass of the movable EC supplying device as awhole changes as the number of the component supplying units mounted onthe movable table changes, or as the number of the ECs stored in each ofthe supplying units changes. Also, the speed of operation of the ECmounter changes. However, the vibration damping characteristic of thedamper can be adjusted depending upon those changes, so that theamplitude of vibration of the floor is not increased.

(6) According to a sixth feature of the present invention that includesthe fifth feature (5), the adjustable damper comprises a movable memberwhich is movable as a unit with the base member; a stationary memberwhich is substantially immovable relative to the floor surface; afriction member which is held by one of the movable and stationarymembers such that the friction member is movable toward, and away from,the other of the movable and stationary members and is frictionallycontactable with the other of the movable and stationary members; and apressing device which is provided between the friction member and theone of the movable and stationary members and which presses, with anadjustable pressing force, the friction member against the other of themovable and stationary members. Since the friction member is pressedagainst the other of the movable and stationary members, friction occursbetween the friction member and the other member, so that thevibrational energy is transformed into thermal energy. Consequently thevibration is damped. The vibration damping characteristic of the dampercan be adjusted by adjusting the pressing force of the pressing deviceapplied to the friction member.

(7) According to a seventh feature of the present invention thatincludes the sixth feature (6), the pressing device comprises afluid-pressure-operated cylinder device which includes a cylinder and apiston and which is fixed to the one of the movable and stationarymembers, the piston pressing the friction member against the other ofthe movable and stationary members. The fluid-pressure-operated cylinderdevice may be an air- or liquid-pressure-operated cylinder device. Ineither case, the pressing force can be adjusted by adjusting thepressure of the fluid. The friction member may be fixed to the piston,or may be supported by the one of the movable and stationary memberssuch that the friction member is movable in a direction parallel to thedirection of movement of the piston.

(8) According to an eighth feature of the present invention thatincludes any one of the first to seventh features (1) to (7), the dampercomprises an unadjustable damper which has an unadjustable vibrationdamping characteristic. Even the unadjustable damper whose vibrationdamping characteristic is not adjustable can damp the relative vibrationof the base member and the floor, thereby preventing the amplificationof the vibration of the EC mounter and the resonance of the same. In aparticular case where it is not needed to adjust all the vibrationdamping capability of the present mounter supporting apparatus, it ispossible to employ both the adjustable damper or dampers and theunadjustable damper or dampers, which contributes to reducing theproduction cost of the present apparatus.

(9) According to a ninth feature of the present invention that includesany one of the first to eighth features (1) to (8), the mountersupporting apparatus further comprises at least one inclinationadjusting device which is provided between the base member and the floorsurface and which adjusts an inclination of the base member relative tothe floor surface. Since the EC mounter is supported on the floor viathe elastic member such that the base member and the floor can bevibrated relative to each other, the base member is easily inclinedrelative to the floor surface. For example, it is difficult to produce aplurality of elastic members which can support, in the state of beingelastically deformed, the base member such that the base member is notinclined relative to the floor surface. Thus, the base member is easilyinclined because of the production-related errors of the elasticmembers. In addition, the weight of the EC supplying device as a wholechanges as the number of the component supplying units employed changesor as the number of ECs stored in each of the component supplying unitschanges. This change also causes the inclination of the base member. Theinclination adjusting device easily adjusts the inclination of the basemember and keeps the base member parallel to the floor surface. Thus,the EC mounter does not fail to receive or pass the circuit substratefrom or to its peripheral devices.

(10) According to a tenth feature of the present invention that includesthe ninth feature (9), the inclination adjusting device comprises a gasspring which comprises a gas chamber and a compressible gas enclosed inthe gas chamber; and a leveling valve device which adjusts a pressure ofthe compressible gas enclosed in the gas chamber of the gas spring andthereby adjusts the inclination of the base member relative to the floorsurface. The gas may be air or nitrogen gas. The leveling valve devicemay be one which adjusts the gas pressure of the gas spring so as tokeep a predetermined height of the gas spring.

(11) According to an eleventh feature of the present invention thatincludes the tenth feature (10), the leveling valve device comprises amechanical valve device which is provided between the base member andthe floor surface and which adjusts the inclination of the base memberrelative to the floor surface, based on movement of the base member andthe floor surface relative to each other in a direction intersecting ahorizontal plane. The leveling valve device may include asolenoid-operated switch valve device. However, this switch valve deviceis selectively switched between its gas-supply position where the valvepermits a pressurized gas to be supplied from a gas source to the gasspring and its gas-relieve position where the valve device permits thegas to be relieved from the gas spring into the atmosphere. Thus, thesolenoid-operated switch valve device cannot finely control or changethe gas pressure of the gas spring. In contrast, the mechanical valvedevice can be gradually switched between its gas-supply position and itsgas-relieve position, and can finely change the gas pressure of the gasspring. Thus, the mechanical valve device can accurately adjust theinclination of the base member.

(12) According to a twelfth feature of the present invention thatincludes any one of the first to eleventh features (1) to (11), themounter supporting apparatus comprises a plurality of the elasticmembers each of which is provided between the base member and the floorsurface; a plurality of the dampers each of which damps the vibration ofthe base member and the floor surface relative to each other; aplurality of upper members each of which is fixed to the base member;and a plurality of lower members each of which is provided on the floorsurface, at least one first elastic member of the plurality of elasticmembers and at least one first damper of the plurality of dampers beingprovided between at least one first upper member of the plurality ofupper members and at least one first lower member of the plurality oflower members, so as to provide a first supporting unit, at least onesecond elastic member of the plurality of elastic members and at leastone second damper of the plurality of dampers being provided between atleast one second upper member of the plurality of upper members and atleast one second lower member of the plurality of lower members, so asto provide a second supporting unit, the first and second supportingunits cooperating with each other to support the base member, atrespective locations which are distant from each other in a horizontaldirection. The horizontal direction is not limited to a specificdirection. The two supporting units can stably support the base memberrelative to the floor surface. The respective dampers of the twosupporting units may be either adjustable ones or unadjustable ones.

(13) According to a thirteenth feature of the present invention thatincludes the twelfth feature (12), the at least one first upper membercomprises an elongate first upper member, the at least one first lowermember comprises an elongate first lower member, the at least one secondupper member comprises an elongate second upper member, and the at leastone second lower member comprises an elongate second lower member, andthe first supporting unit comprises two first elastic members one ofwhich is provided at one of lengthwise opposite end portions of theelongate first upper member and one of lengthwise opposite end portionsof the elongate first lower member and the other of which is provided atthe respective other end portions of the elongate first upper and lowermembers, and two first dampers one of which is provided at therespective one end portions of the elongate first upper and lowermembers, and the other of which is provided at the respective other endportions of the elongate first upper and lower members, and the secondsupporting unit comprises two second elastic members one of which isprovided at one of lengthwise opposite end portions of the elongatesecond upper member and one of lengthwise opposite end portions of theelongate second lower member and the other of which is provided at therespective other end portions of the elongate second upper and lowermembers, and two second dampers one of which is provided at therespective one end portions of the elongate second upper and lowermembers and the other of which is provided at the respective other endportions of the elongate second upper and lower members. According tothis feature, at least four elastic members and at least four dampersare provided at respective locations corresponding to the four cornersof the base member. Thus, the supporting units can more stably supportthe base member relative to the floor surface, while permitting the basemember to move relative to the floor surface.

(14) According to a fourteenth feature of the present invention thatincludes the twelfth or thirteenth feature (12) or (13), theelectric-component supplying device comprises a component-supply tableand a plurality of component supplying units which are provided on thecomponent-supply table such that respective component-supply portions ofthe component supplying units are arranged along a straight line, andthe mounter supporting apparatus further comprises an inclinationadjusting device which is provided between the floor surface and aportion of the base member that supports the component-supply table, andwhich adjusts an inclination of the base member relative to the floorsurface. The number of the component supplying units provided on thecomponent-supply table may be changed depending upon, e.g., the sort ofthe circuit substrate used, and the number of ECs stored in each of thecomponent supplying units decreases as the ECs are mounted one by one onthe substrate. Thus, the weight of the EC supplying device changes.Therefore, the base member is inclined relative to the floor surface ina direction perpendicular to the direction in which the respectivecomponent-supply portions of the component supplying units are arranged.However, the inclination adjusting device can keep the base membersubstantially parallel to the floor surface.

(15) According to a fifteenth feature of the present invention thatincludes the fourteenth feature (14), the mounting device receives, at apredetermined component-receive position, the electric components fromthe electric-component supplying device, the straight line along whichthe respective component-supply portions of the component supplyingunits are arranged passes through the component-receive position, andthe electric-component supplying device comprises a movableelectric-component supplying device which comprises the component-supplytable comprising a movable table which is movable along the straightline, and the component supplying units having the respectivecomponent-supply portions each of which is selectively positioned at thecomponent-receive position by the movement of the movable table, and thefirst and second supporting units are provided at the respectivelocations which are distant from each other in the horizontal directionparallel to the straight line, and each of the first and second dampersof the first and second supporting units has a function of damping therelative vibration of the base member and the floor surface in alldirections on at least a vertical plane parallel to the straight line.Since the movable table has a great mass, the base member is subjectedto a great vibrational force in a direction parallel to the straightline passing through the component-receive position. However, accordingto this feature, the two supporting units are provided at the respectivelocations distant from each other in that direction. In addition, thedampers damp the relative vibration of the base member and the floorsurface in all directions on the vertical plane parallel to thedirection of movement of the table. Thus, the vibration which istransmitted to the floor is reduced, and the vibration of the EC mounteris reduced. Irrespective of where the movable table is started orstopped within its movement area or irrespective of whether the table ismoved forward or backward along the straight line, the two supportingunits permit the relative vibration of the base member and the floorsurface, while damping the same. As the movable table is moved, thebalance of respective loads applied to respective portions of the basemember that are distant from each other in the direction of movement ofthe table changes, so that the base member is inclined. Therefore, it ispreferred that one or more inclination adjusting devices be provided foradjusting the inclination of the base member in that direction. Forexample, two inclination adjusting devices each of which adjusts thedistance between the base member and the floor surface are provided atrespective locations which are distant from each other in the directionof movement of the table. Each of the two inclination adjusting devicesmay include the above-described combination of the gas spring and theleveling valve device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and optional objects, features, and advantages of the presentinvention will be better understood by reading the following detaileddescription of the preferred embodiments of the invention whenconsidered in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic plan view of an electric-component ("EC") mounterwhich is supported by an EC-mounter supporting apparatus to which thepresent invention is applied;

FIG. 2 is a plan view of the EC-mounter supporting apparatus of FIG. 1and a frame as a base member of the EC mounter;

FIG. 3 is a front elevation view of the EC-mounter supporting apparatusof FIG. 1;

FIG. 4 is a plan view of a leveling valve device of an inclinationadjusting device as an element of the EC-mounter supporting apparatus ofFIG. 1;

FIG. 5 is a front elevation view of the leveling valve device of FIG. 4;

FIG. 6 is a diagrammatic view for explaining a manner in which air issupplied to a direction control valve of the leveling valve device ofFIG. 4;

FIG. 7 is a bottom view of one end portion of an upper member of asupporting unit as an element of the EC-mounter supporting apparatus ofFIG. 1;

FIG. 8 is a plan view of one end portion of a lower member of thesupporting unit of FIG. 7;

FIG. 9 is a partly cross-sectioned, front elevation view showing acompression coil spring as an element of the supporting unit of FIG. 7,in a state in which the coil spring is engaged with the upper and lowermembers;

FIG. 10 is a partly cross-sectioned, front elevation view showing apressing device as an element of the supporting unit of FIG. 7; and

FIG. 11 is a plan view of another EC-mounter supporting apparatus as asecond embodiment of the present invention, and a frame as a base memberof an EC mounter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, there will be described an electric-component ("EC")mounter supporting apparatus 12 (FIG. 2) to which the present inventionis applied. The EC-mounter supporting apparatus 12 supports an ECmounter 14, on a horizontal surface 10 of a floor. The EC mounter 14includes a printed-circuit-board ("PCB") supporting device 16, amounting device 18, and a movable EC supplying device 20, and a basemember 22 which supports the three devices 16, 18, 20.

The PCB supporting device 16 includes an X-axis table 28 which ismovable in an X-axis direction indicated at an arrow in FIG. 1; and aY-axis table 30 which is provided on the X-axis table 28 and which ismovable in a Y-axis direction, indicated at an arrow in FIG. 1,perpendicular to the X-axis direction on a horizontal plane. On theY-axis table 30, there is provided a board holding device (not shown)which positions and holds a PCB 32 as a circuit substrate.

The X-axis table 28 is moved in the X-axis direction by an X-axis-tablemoving device 37, while being guided by a pair of straight guide rails38 as guide members. The X-axis-table moving device 37 includes anX-axis servomotor 34 as a drive source, and a motion converting devicewhich includes a feed screw 36 and a nut (not shown) and converts therotation of the X-axis servomotor 34 into a linear motion of the X-axistable 28. The Y-axis table 30 is moved in the Y-axis direction by aY-axis-table moving device 43, while being guided by a pair of straightguide rails 44 as guide members. The Y-axis-table moving device 43includes a Y-axis servomotor (not shown) as a drive source, and a motionconverting device which includes a feed screw 42 and a nut (not shown)and converts the rotation of the Y-axis servomotor into a linear motionof the Y-axis table 30.

The PCB 32 is carried in onto the PCB supporting device 16 by a PCBcarry-in conveyor 46, and carried out from the device 16 by a PCBcarry-out conveyor 48. The two conveyors 46, 48 are provided on thefloor surface 10, and are connected to each other by a connection member(not shown). Each of the two conveyors 46, 48 conveys the PCB 32 in theX-axis direction. The board holding device provided on the Y-axis table30 is vertically movable between its upper stroke end position where theholding device receives the PCB 32 from the PCB carry-in conveyor 46 andpasses the same 32 to the PCB carry-out conveyor 48, and its lowerstroke end position where the holding device is moved with the X-axistable 28 and the Y-axis table 30 so that a number of EC-mount places onthe PCB 32 are sequentially positioned at a predetermined EC-mountposition.

The mounting device 18 has the same construction as that of a mountingdevice disclosed in Japanese Patent Application laid open for publicinspection under Publication No. 9(1997)-237997 corresponding to U.S.patent application Ser. No. 08/769,700. Therefore, the mounting device18 will be described briefly. The mounting device 18 includes a mainframe (not shown) which is provided on the base member 22; a pluralityof rotary plates 60 as rotary members (in the present embodiment, twelverotary plates 60 are employed); a rotary-plate rotating device as arotary-motion applying device which applies a rotary motion to each ofthe rotary plates; and a plurality of EC holding heads 62 which aresupported by the plurality of rotary plates 60, respectively (in thepresent embodiment, twelve EC holding heads 62 are employed). The rotaryplates 60 are attached to a vertical axis member 64 (FIG. 1) supportedby the main frame, such that the rotary plates 60 are rotated about theaxis member 64, independent of each other. The EC holding heads 62 aresupported by the rotary plates 60, respectively, such that the holdingheads 62 are vertically movable relative to the corresponding rotaryplates 60. Each EC holding head 62 as a sort of EC holder includes an ECsucker (not shown) which sucks and holds an EC by applying a negativeair pressure thereto.

The rotary-plate rotating device include twelve rollers (not shown) ascam followers which are provided on the twelve rotary plates 60,respectively; and four globoidal cams as rotary-motion applying camseach of which sequentially engages the twelve rollers and thereby movesor rotates each of the twelve rotary plates 60. The four globoidal camsare rotated in synchronism with one another by a cam drive deviceincluding a servomotor as its drive source, so that the twelve rotaryplates 60 are rotated independent of each other and the twelve ECholding heads 62 are revolved around the axis member 64. Three rotaryplates 60 of the twelve rotary plates 60 are simultaneously stopped atan EC-suck position as an EC-receive position, an EC-image-takeposition, and the EC-mount position, respectively. At the EC-suckposition, a first EC holding head 62 sucks and holds an EC; at theEC-image-take position, an image of an EC held by a second EC holdinghead 62 is taken; and at the EC-mount position, a third EC holding head62 mounts an EC on the PCB 32. While the three rotary plates 60 arestopped, the other, nine rotary plates 60 are rotated about the axismember 64. Since each of the EC holding heads 62 can reach each of theEC-suck position, the EC-image-take position, and the EC-mount position,at a short time interval or pitch, the EC mounting device 18 enjoys ahigh EC-mount efficiency.

The EC-suck position and the EC-mount position are distant from eachother by 180 degrees, and are aligned with each other in the Y-axisdirection. The movable EC supplying device 20 and the PCB supportingdevice 16 are provided at respective positions corresponding to theEC-suck and EC-mount positions, respectively. At each of thosepositions, a head elevating and lowering device is provided, forelevating and lowering each EC holding head 62 being positioned at theEC-suck or EC-mount position, so that the each EC holding head 62 holdsor mounts an EC. At the EC-image-take position, there is provided a CCD(charge coupled device) camera (not shown) as an image taking device.The EC sucker of each of the EC holding heads 62 is rotatable about itsaxis line, and is rotated about its axis line by an EC-sucker rotatingdevice (not shown) provided on the corresponding one of the rotaryplates 60. Thus, a rotation-position error of the EC sucker can becorrected. A portion of the PCB supporting device 16 is located belowthe mounting device 18, and another portion of the same 16 is locatedbelow respective upper portions of the PCB carry-in and carry-outconveyors 46, 48.

As shown in FIG. 1, the movable EC supplying device 20 includes amovable table 70, and a plurality of EC supplying units 72 each of whichis detachably attached to the movable table 70. Each of the EC supplyingunits 72 supplies an EC carrier tape which carries a plurality of ECsand which is wound around a tape reel. The tape reel is rotatablysupported by a tape storing device as an EC storing device, and the tapestoring device is provided on a main frame of the each EC supplying unit72. The carrier tape drawn from the tape reel is fed to a tape feedingdevice as an EC feeding device provided on the main frame. Thus, Thetape feeding device feeds the ECs one by one to an EC-supply portion ofthe each EC supplying unit.

The plurality of EC supplying units 72 are detachably attached to themovable table 70 such that the respective EC-supply portions of theunits 72 are arranged along a straight line parallel to the X-axisdirection. This straight line passes through the EC-suck position of themounting device 18, and the movable table 70 is moved by a movable-tablemoving device 74 in the X-axis direction, that is, along the straightline passing through the EC-suck position. Hereinafter, the direction ofmovement of the movable table 70 will be referred to as the"table-movement" direction. The table-movement direction is parallel tothe direction in which the PCB carry-in and carry-out conveyors 46, 48conveys the PCB 32.

The movable-table moving device 74 includes a table-moving servomotor 76as a drive source, and a motion converting device which includes a feedscrew 78 and a nut (not shown) and converts the rotation of theservomotor 76 into a linear movement of the movable table 70. Themovable table 70 is moved by the moving device 74 while being guided bya pair of straight guide rails 80 as guide members. Thus, each of therespective EC-supply portions of the EC supplying units 72 isselectively positioned at the EC-suck position of the mounting device18. The positioning of each EC-supply portion at the EC-suck positionmeans the positioning of the corresponding EC supplying unit 72 at theEC-suck position. The EC-suck position of the mounting device 18coincides with an EC-supply position of the movable EC supplying device20. The EC-supply portion of one EC supplying unit 72 being positionedat the EC-supply position is positioned below one EC holding head 62being positioned at the EC-suck position. Each of the servomotors thatare employed as the X-axis-table drive motor 34, the Y-axis-table drivemotor, the movable-table moving motor 76, and the cam drive motor of therotary-plate rotating device, is an electric rotary motor as a sort ofelectric motor that is precisely controllable with respect to itsrotation angle and rotation speed. Those servomotors may be replacedwith stepper motors.

As shown in FIGS. 2 and 3, the EC-mounter supporting apparatus 12 isprovided between the floor surface 10 and a frame 88 as the base member22 of the EC mounter 14, and includes an inclination adjusting device90, three spring units 92, and two supporting units 94. It is assumedthat the floor surface 10 is horizontal. However, in some cases, thefloor surface 10 may not be horizontal for some reason. In such cases,one or more adjust members is or are placed, on the floor surface 10, atone or more of respective locations where the inclination adjustingdevice 90, the spring units 92, and the supporting units 94 are to belocated, so that the EC-mounter supporting apparatus 12 may be providedon a horizontal plane defined by the one or more adjust members and/orthe floor surface 10.

The inclination adjusting device 90 includes an air spring 96 as a sortof gas spring, and a mechanical valve device 98. The adjusting device 90is provided between the floor surface 10 and a portion of the frame 88that supports the movable table 70. More specifically, this portion is amiddle portion of a table-movement area in which the movable table 70 ismoved, as seen in the table-movement direction (i.e., the X-axisdirection), and is adjacent to the mounting device 18 as seen in adirection (i.e., the Y-axis direction) perpendicular to thetable-movement direction on a horizontal plane. Hereinafter, thisperpendicular direction (i.e., the Y-axis direction) will be referred toas the "front-rear" direction, if appropriate. The PCB supporting device16 is provided on the front side, and the movable EC supplying device 20is provided on the rear side, as seen in the front-rear direction. Thus,the inclination adjusting device 90 is provided between the floorsurface 10 and a rear portion of the frame 88. The air spring 96 isformed of a rubber, has a cylindrical shape, and is provided between thefloor surface 10 and the frame 88. The air spring 96 has an air chamberin which air is enclosed. The elasticity of the air spring 96 can beadjusted by adjusting the pressure of the air enclosed in the airchamber thereof.

As shown in FIGS. 4 and 5, the mechanical valve device 98 includes adirection control valve 100 and a dog device 102. A housing 104 of thedirection control valve 100 is fixed to the floor surface 10, and isconnected via a connection member (not shown) to a pressurized-airsource 106 (FIG. 6) as a pressurized-gas source, and the air spring 96.The direction control valve 100 is provided by a spool valve as a sortof port valve, and includes a spool (not shown) which is accommodated inthe valve housing 104 such that the spool is movable in the housing 104.The direction control valve 100 is selectively switched, by the movementof the spool, to an air-supply state in which the valve 100 allows theair spring 96 to be communicated with the pressurized-air source 106 sothat a pressurized air is supplied to the air spring 96, and anair-relieve state in which the valve 100 allows the air spring 96 to becommunicated with the atmosphere so that the pressurized air is relievedfrom the air spring 96. The spool of the valve 100 has two land portionscorresponding to two ports of the housing 104 one of which communicateswith the air source 106 and the other of which communicates with theatmosphere. The housing 104 has a third port which communicates with theair spring 96. An axial length of each of the two land portions of thespool is equal to, or just slightly greater than, a diameter of each ofthe two ports of the housing 104. The spool is moved by a pivotal motionof a pivotable lever 108 as an engaging member that is pivotallysupported by the housing 104. In the state in which the pivotable lever108 is positioned at a reference rotation or angular position, a portionof the pressurized air supplied from the air source 106 is directlyreleased into the atmosphere, so that the air pressure in the air spring96 is maintained at a certain value. When the lever 108 is pivoted fromits reference position in each one of opposite directions, the spool ismoved in a corresponding one of opposite directions, so that the valve100 is switched to a corresponding one of the air-supply and air-relievepositions. Consequently the air pressure in the air spring 96 ischanged. As far as the present embodiment is concerned, the referenceposition of the pivotable lever 108 is defined as a position where thelever 108 takes a horizontal posture.

As shown in FIG. 6, a normally open pilot-type shut-off valve 110 and anormally closed pilot-type shut-off valve 112 are provided between thedirection control valve 100 and the pressurized-air source 106. Thevalve closing pressure of the normally open valve 110 is higher than thepressure of the pressurized air supplied to the air spring 96, and thevalve opening pressure of the normally closed valve 112 is slightlyhigher than the valve closing pressure. Owing to the two shut-off valves110, 112, the pressure of the pressurized air supplied from the airsource 106 is decreased to a desirable value before the air reaches thedirection control valve 100.

As shown in FIG. 5, the dog device 102 includes a dog 118 which isattached via a screw member 116 to the frame 88, such that a heightposition of the dog 118 is adjustable. The dog 118 has a pair of flangeportions 120 which extend radially outwardly. A roller 122 which isrotatably attached to a free end portion of the pivotable lever 108, asan engaging portion of the same 108, is inserted in an inner spacedefined, by and between, the two flange portions 120 of the dog 118.

The height position of the dog 118 is adjusted by an operator whorotates the screw member 116, such that the pivotable lever 108 takesits horizontal posture and the air pressure in the air spring 96 ismaintained at a certain value, in the state in which the frame 88 isparallel to the floor surface 10. The adjustment of the height positionof the dog 118 may be carried out, for example, when the EC mounter 14is disposed on the frame 88 in such a manner that the movable table 70on which no EC supplying units 72 have been mounted is positioned at themiddle of the table-movement area as seen in the table-movementdirection, i.e., the X-axis direction. As the weight of the movable ECsupplying device 20 changes and the frame 88 is accordingly inclinedrelative to the floor surface 10 in the front-rear direction, thepivotable lever 108 is automatically pivoted by the dog 118, so that thedirection control valve 100 is switched from the reference position toeither one of the air-supply and air-relieve positions. Thus, the airpressure in the air spring 96 is automatically changed or adjusted to anappropriate value which can keep the horizontal posture of the lever 108and an appropriate height of the air spring 96 that was initially takenby the same 96 when the height position of the dog 118 was adjusted.Accordingly, the inclination of the frame 88 relative to the floorsurface 10 in the front-rear direction is prevented and the frame 88 iskept parallel to the floor surface 10. Thus, the dog device 102functions not only as a switching device which switches the directioncontrol valve 100 and which includes the dog 118 as a switching member,and but also as a dog-height-position adjusting device as a sort ofrelative-height-position adjusting device which adjusts the heightposition of the switching member (i.e., dog 118) relative to the valve100. The relative-height-position adjusting device may be one whichadjusts the height position of the valve 100 relative to the dog 118, orone which adjusts the height position of each one of the dog 118 and thevalve 100 relative to the other of the dog 118 and the valve 100.

The three spring units 92 are available from a commercial market. Eachof the spring units 92 includes a compression coil spring as a springmember as a sort of elastic member, and a damper (not shown). Thecompression coil spring and the damper are provided in series in avertical direction, between the floor surface 10 and the frame 88. Thedamper has a silicone chamber and a mass of silicone enclosed in thechamber. The damper damps the vibration of the frame 88 and the floorsurface 10 relative to each other resulting from the compression andexpansion of the coil spring. This damper is an unadjustable damperwhose vibration damping characteristic is not adjustable. As shown inFIG. 2, two of the three spring units 92 are provided on both sides ofthe inclination adjusting device 90 in the X-axis direction (i.e., thetable-movement direction), respectively, that is, at respectivelocations distant from each other in the X-axis direction and betweenthe floor surface 10 and a rear end portion of the frame 22. The thirdspring unit 92 is provided at a location distant from the inclinationadjusting device 90 in the Y-axis direction and between the floorsurface 10 and a front end portion of the frame 22.

Next, the two supporting units 94 will be described. As shown in FIG. 2,the two supporting units 94 are provided at respective locations distantfrom each other in the table-movement direction parallel to a lengthwisedirection of the frame 88. Since the two supporting units 94 have thesame construction, one of the two units 94 will be described below as arepresentative thereof.

As shown in FIGS. 2, 7, 8, 9, and 10, one supporting unit 94 includes anupper member 130, a lower member 132, four compression coil springs 134as a sort of elastic members that are provided between the upper andlower members 130, 132, and eight adjustable dampers 136.

As shown in FIGS. 8 and 9, the lower member 132 is an elongate memberhaving a generally U-shaped cross section. The lower member 132 isplaced on the floor surface 10 via a pad 140 such that the openingthereof faces upward and the lengthwise direction thereof isperpendicular to the table-movement direction on a horizontal plane. Thepad 140 includes an elastic sheet which is formed of a rubber, or aresin having a certain degree of elasticity, and two tacky layers whichare provided on opposite surfaces of the elastic sheet. Thus, the pad140 has a certain degree of tackiness, and is fixed to the floor surface10 and the lower member 132. Therefore, the lower member 132 isprevented from being moved relative to the floor surface 10. Inaddition, owing to the elasticity of the pad 140, the lower member 132is kept stable on the floor surface 10. Thus, each of the two pads 140provides a fixing member for fixing a corresponding one of the two lowermembers 132, or a corresponding one of the two supporting units 94, tothe floor surface 10. The lower members 132 provide stationary members.

Two spring retainers 142 are fixed to each of lengthwise opposite endportions of the lower member 132. Thus, four spring retainers 142 intotal are provided on the lower member 132. However, FIG. 8 shows onlytwo retainers 142 fixed to one end portion of the lower member 132. Eachof the four spring retainers 142 has a circular cross section, andprojects upward from the lower member 132. The two spring retainers 142provided on each of the two end portions of the lower member 132 arearranged side by side in the table-movement direction.

On each of the lengthwise opposite end portions of the lower member 132,four friction members 144 and four air-pressure-operated cylinderdevices (hereinafter, abbreviated to the "air cylinders") 146 areprovided in the vicinity of the two spring retainers 142 in thelengthwise direction of the lower member 132. FIG. 8 shows the fourfriction members 144 and the four air cylinders 146 provided on one ofthe two end portions of the lower member 132. Since the friction members144 and the air cylinders 146 provided on the one end portion areidentical with those 144, 146 provided on the other end portion, onlythe friction members 144 and the air cylinders 146 provided on the oneend portion will be described below.

A cylinder housing 148 is provided, as an integral portion of the lowermember 132, in the vicinity of the spring retainers 142. The cylinderhousing 148 has two cylindrical bores 150 which are formed through thehousing 148 in a direction parallel to the lengthwise direction of thelower member 132 and perpendicular to the table-movement direction on ahorizontal plane. Two pistons 152 are airtightly and slideably fitted ineach of the two bores 150, such that the two pistons 152 face inopposite directions.

The two pistons 152 fitted in each of the two cylindrical bores 150project outward in the opposite directions from opposite end surfaces ofthe cylinder housing 148 in the lengthwise direction of the lower member132. The four friction members 144 are fixed to respective end surfacesof the four pistons 152 projecting outward from the housing 148. Thus,the four air cylinders 146 extend perpendicular to the table-movementdirection on the horizontal plane and parallel to the lengthwisedirection of the lower member 132, and the four friction members 144vertically extend parallel to the table-movement direction.

One air chamber 154 is defined by, and between, the two pistons 152fitted in each of the two cylindrical bores 150. As shown in FIG. 6, thetwo air chambers 154 are connected to the pressurized-air source 106.Between the air chambers 154 and the air source 106, there are provideda normally open pilot-type variable shut-off valve 158 and a normallyclosed pilot-type variable shut-off valve 160 each of which includes aspring incorporated therein. The valve closing pressure of the normallyopen valve 158 and the valve opening pressure of the normally closedvalve 160 can be adjusted by changing respective biasing forces of therespective springs of the valves 158, 160. Thus, the pressure of thepressurized air supplied to the air chambers 154 can be adjusted. Thevalve closing pressure can be predetermined to be equal to a desirableair pressure to be supplied to the air chambers 154, and the valveopening pressure can be predetermined to be slightly higher than thedesirable air pressure. Thus, the pressurized air with the desirablepressure can be supplied to the air chambers 154.

As shown in FIG. 10, one of the lengthwise opposite end portions of eachof the respective lower members 132 of the two supporting units 94 isprovided with an engaging member 162. The PCB carry-in conveyor 46 isheld in engagement with the engaging member 162 of one of the twosupporting units 94, and the PCB carry-out conveyor 48 is held inengagement with the engaging member 162 of the other supporting unit 94.

The lower member 132 is provided with two pairs of connection members164 at respective positions distant from each other in the lengthwisedirection of the lower member 132. FIG. 8 shows only one pair ofconnection members 164 provided at one of the two distant positions.Each of the connection members 164 has a generally U-shaped recess 166which is formed through the thickness of the each member 164 in avertical direction and opens outward in a horizontal direction. Thefunction of the connection members 164 will be described later.

As shown in FIGS. 7 and 9, the upper member 130 is an elongate memberhaving a generally U-shaped cross section. Two spring retainers 170 arefixed to each of lengthwise opposite end portions of the upper member130. Thus, four spring retainers 170 in total are provided on the uppermember 130. However, FIGS. 7 and 9 show only two retainers 170 fixed toone end portion of the upper member 130. Each of the four springretainers 170 has a circular cross section, and projects downward fromthe upper member 130. The two spring retainers 170 provided on each ofthe two end portions of the upper member 130 are arranged side by sidein the table-movement direction. The upper member 130 is provided suchthat the opening thereof faces downward and the lengthwise directionthereof is perpendicular to the table-movement direction. Each of thefour spring retainers 170 cooperates with a corresponding one of thefour spring retainers 142 provided on the lower member 132 to retainopposite end portions of a corresponding one of the four compressioncoil spring 134. Thus, each of the lengthwise opposite end portions ofeach of the upper and lower members 130, 132 is provided with the twocompression coil springs 134. It can be said that each of the two endportions of each of the two supporting units 94 is provided with a groupof spring members, i.e., the two coil springs 134.

As shown in FIG. 7, on each of the lengthwise opposite end portions ofthe upper member 130, two friction ribs 172 are provided in the vicinityof the two spring retainers 170 in the lengthwise direction of the uppermember 130, such that the two friction ribs 172 are distant from eachother in a direction perpendicular to the table-movement direction, thatis, in the lengthwise direction of the upper member 130. FIG. 7 showsthe two friction ribs 172 provided on one of the two end portions of theupper member 130. The friction ribs 172 extend perpendicular to thelengthwise direction of the upper member 130 and parallel to a widthwisedirection of the same 130. That is, the friction ribs 172 verticallyextend parallel to the table-movement direction. The friction ribs 172provide movable members. The four friction members 144 and the four aircylinders 146 provided on each of the two end portions of the lowermember 132 are fitted in a space defined by, and between, the twofriction ribs 172 provided on a corresponding one of the two endportions of the upper member 130. Thus, respective surfaces of the fourfriction members 144 are pressed against respective surfaces of the twofriction ribs 172 by the four air cylinders 146. Those surfaces of thefriction members and ribs 144, 172 will be referred to as the "frictionsurfaces". The friction surfaces are vertical, and parallel to thetable-movement direction. Thus, the four friction members 144, the fourair cylinders 146, the two friction ribs 172, and one of the two endportions of the lower member 132 cooperate with one another to providethe four adjustable dampers 136. That is, the four adjustable dampers136 are provided at each of the lengthwise opposite end portions of eachof the two supporting units 94. It can be said that each of the two endportions of each of the supporting units 94 is provided with a group ofdampers, i.e., the four adjustable dampers 136. Thus, the EC-mountersupporting apparatus 12 includes the four group of spring members andthe four groups of dampers which are provided at respective locationscorresponding to the four corners of the frame 88 as the base member 22.

As shown in FIG. 9, the frame 88 as the base member 22 is placed on thetwo upper members 130 via respective pads 174. Like the above-describedpads 140, each of the pads 174 includes an elastic sheet and two tackylayers applied to opposite surfaces of the elastic sheet. Thus, each ofthe two pads 174 has some degree of tackiness, and is firmly fixed tothe frame 88 and a corresponding one of the upper members 130.Therefore, the frame 88 is prevented from being moved relative to theupper members 130, and accordingly the frame 88 is kept stable on theupper members 130. Thus, the pads 174 provide fixing members forsubstantially fixing the frame 88, i.e., the base member 22 to the uppermembers 130.

Like the lower members 132, each of the upper members 130 is providedwith two pairs of connection members 176 at respective positions distantfrom each other in the lengthwise direction of the each upper member130. FIG. 7 shows only one pair of connection members 176 provided atone of the two distant positions. Each of the connection members 176 hasa generally U-shaped recess 178 similar to each of the respectiverecesses 166 of the connection members 164.

When the EC mounter 14 is disposed on the floor surface 10 via theEC-mounter supporting apparatus 12, the two upper members 130 areopposed to the two lower members 132, respectively, such that thedownward openings of the upper members 130 face the upward openings ofthe lower members 132, respectively. In addition, as shown in FIG. 9,the upper spring retainers 170 and the lower spring retainers 142cooperate with each other to retain the compression coil springs 134.Screw members such as bolts are passed through the pairs of recesses166, 178 of the connection members 164, 176 of the lower and uppermembers 132, 130, respectively, and nuts are threadedly engaged with thescrew members, respectively, till each pair of connection members 164,176 are closely contacted with each other. Thus, the two upper members130 are firmly combined with the two lower members 132, respectively.Consequently the compression coil springs 134 are pre-compressed.

After the lower members 132 are placed on the floor surface 10 via thepads 140 and the frame 88 as the base member 22 is placed on the uppermembers 130 via the pads 174, the nuts are removed from the screwmembers, respectively, so that the upper members 130 are released fromthe lower members 132, respectively. On the frame 88, the PCB supportingdevice 16, the mounting device 18, and the movable table 70 and themovable-table moving device 74 of the movable EC supplying device 20have already been mounted. Since the upper members 130 are released fromthe lower members 132, the compression coil springs 134 are more or lessexpanded and the upper members 130 are more or less separated from thelower members 132. The distance of the upper members 130 from thecorresponding lower members 132 depends on the load of the EC mounter 14acting on the upper members 130 and the spring characteristic of thecompression coil springs 134. Thus, as shown in FIG. 9, the uppermembers 130 are allowed to move relative to the lower members 132because of the expansion and compression of the coil springs 134. Sincethe upper and lower members 130, 132 hold the upper and lower endportions of the coil springs 134, the members 130, 132 are preventedfrom being dislocated relative to the springs 134 and accordingly theframe 88 is prevented from being dislocated relative to the floorsurface 10. In addition, as shown in FIG. 10, the friction ribs 172 areopposed to the friction members 144 and, when the pressurized air issupplied to the air chambers 154 of the air cylinders 146, the frictionmembers 144 are pressed against the friction ribs 172. After the ECmounter 14 is placed on the floor surface 10 via the supporting units 94in this way, the three spring units 92 and the inclination adjustingdevice 90 are disposed between the frame 88 and the floor surface 10.

When ECs are mounted on a PCB 32, the drive motor (i.e., servomotor) ofthe cam drive device drives the four globoidal cams, so that the twelverotary plates 60 are rotated independent of one another and the ECholding heads 62 are sequentially moved to the EC-suck position, theEC-image-take position, and the EC-mount position. After the EC suckerof each holding head 62 sucks up an EC from the EC-supply portion of oneEC supplying unit 72 being positioned at the EC-receive position (i.e.,EC-suck position), an image of the EC held by the EC sucker is taken bythe CCD camera. A control device (i.e., computer) to which the CCDcamera is connected calculates respective errors of the actual positionof the EC from its reference position in the X-axis and Y-axisdirections, and an error of the actual rotation position of the EC fromits reference rotation position about its axis line. The EC-suckerrotating device rotates the EC sucker and thereby rotates the EC heldthereby, about its axis line, for correcting the rotation-position errorof the EC. Subsequently, the EC is mounted on the PCB 32.

In the movable EC supplying device 20, each of the respective EC-supplyportions of the EC supplying units 72 is selectively positioned at theEC-suck position by the movement of the movable table 70. In the PCBsupporting device 16, each time one EC is mounted on the PCB 32, the PCB32 is moved by the X-axis and Y-axis tables 28, 30, so that the nextEC-mount place on the PCB 32 is positioned below the EC sucker of one ECholding head 62 being positioned at the EC-mount position. The distancesof movement of the X-axis and Y-axis tables 28, 30 are corrected forcompensating the position errors of the center of the EC held by the ECsucker in the X-axis and Y-axis directions, and possible position errorsof the next EC-mount place on the PCB 32 in the X-axis and Y-axisdirections. Before the ECs are mounted on the PCB 32, two referencemarks (not shown) affixed on a diagonal line of the PCB 32 are imaged bya reference-mark-image taking device (not shown) which is connected tothe control device, and the control device calculates, based on thetaken image, the position errors of each of the EC-mount places on thePCB 32 in the X-axis and Y-axis directions. The position errors of thecenter of the EC held by the EC sucker in the X-axis and Y-axisdirections, are the sum of respective position errors of the center ofthe EC produced when the EC is held by the EC sucker and respectiveposition changes of the center of the EC produced when the EC is rotatedfor correcting its rotation-position error.

In the EC mounter 14, when the movable table 70, the X-axis and Y-axistables 28, 30, and the rotary plates 60 are accelerated and decelerated,the frame 88 as the base member 22 is vibrated. Because of the elasticdeformation of the four compression coil springs 134 of each of the twosupporting units 94, the compression coil spring of each of the threespring units 92, and the air spring 96, the frame 88 is allowed to moverelative to the floor surface 10. Thus, the transmission of thevibration of the frame 88 to the floor 10 is avoided. In addition, owingto the respective unadjustable dampers of the spring units 92 and theeight adjustable dampers 136 of each of the two supporting units 94, thevibration of the frame 88 and the floor 10 relative to each other isdamped. Each of the compression coil springs which extend perpendicularto the floor surface 10 can be deformed in each of the verticaldirection, the table-movement direction, and the front-rear direction.Thus, the frame 88 and the floor surface 10 are allowed to be vibratedrelative to each other in all directions. The air spring 96 also allowsthe frame 88 and the floor surface 10 to be vibrated relative to eachother in all directions.

When the frame 88 is moved relative to the floor surface 10, the uppermembers 130 of the supporting units 94 are moved relative to the lowermembers 132 of the same 94. In the adjustable dampers 136, since thefriction members 144 are pressed against the friction ribs 172 by theair cylinders 146, the vibrational energy of the frame 88 and the floor10 is converted into thermal energy. Thus, the vibration of the frame 88and the floor 10 relative to each other is damped. The friction members144 and the friction ribs 172 vertically extend parallel to thetable-movement direction. Thus, the adjustable dampers 136 damp thevibration of the frame 88 and the floor 10 relative to each other in alldirections on the vertical plane parallel to the table-movementdirection. As described previously, the compression coil springs 134 andthe adjustable dampers 136 are provided at respective locationscorresponding to the four corners of the frame 88. Thus, the frame 88 isvery stably supported relative to the floor surface 10. That is, theframe 88 as a whole is allowed to move relative to the floor surface 10,while the vibration of the frame 88 and the floor 10 relative to eachother is damped. The unadjustable dampers of the spring units 92 dampthe vibration of the frame 88 and the floor 10 relative to each other ineach of a vertical direction and a horizontal direction.

The movable table 70 on which the plurality of EC supplying units 72 aremounted has a great mass. Therefore, when the movement of the movabletable 70 is started or stopped, the frame 88 is subjected to avibrational force produced in a direction parallel to the direction ofmovement of the table 70, i.e., the table-movement direction. Asdescribed previously, the frame 88 is also subjected to a rotationalvibration. Thus, portions of the frame 88 that are supported by theEC-mounter supporting apparatus 12 are vibrated in all directions on avertical plane parallel to the table-movement direction. Since, however,the two supporting units 94 are provided at respective positions whichare distant from each other in the table-movement direction, theadjustable dampers 136 effectively damp the vibration of the frame 88and the floor 10 relative to each other in all directions on thevertical plane parallel to the table-movement direction. Thus, not onlythe vibration transmitted to the floor 10 but the vibration transmittedto the EC mounter 14 are largely reduced. This vibration is also dampedby the unadjustable dampers of the spring units 92. When the Y-axistable 30 is moved, the frame 88 is subjected to a vibrational forceproduced in the front-rear direction perpendicular to the table-movementdirection on a horizontal plane. However, this vibration is not solarge. Thus, there arises no problem even if no damper is employed fordamping the vibration of the frame 88 and the floor 10 relative to eachother in the front-rear direction.

The vibration-damping characteristic of each of the adjustable dampers136 is adjustable depending upon each EC mounter 14. This characteristicis adjusted by adjusting the valve closing pressure of the pilot-typevariable shutoff valve 158 and the valve opening pressure of thepilot-type variable shut-off valve 160, and thereby adjusting thepressure of the air supplied to the air chambers 154 of the aircylinders 146, that is, adjusting the pressing force of the aircylinders 146 to press the friction members 144 against the frictionribs 172. This adjustment is carried out when the EC mounter 14 isdisposed on the frame 88 as the base member 22. The EC mounter 14 is runfor trial, and the vibration of the floor 10 produced by this trial runis measured. The air pressure is so determined that the amplitude ofvibration of the floor 10 is small and the amplitude of vibration of themounter 14 is not excessively great. The amplitude of vibration of theEC mounter 14 changes depending upon the conditions of the floor 10,e.g., its rigidity, mass, and vibration-damping characteristic thereof.Hence, it is advantageous to employ the adjustable dampers 136. If, whenthe EC mounter 14 is disposed, the vibration-damping characteristic ofone or more of the adjustable dampers 136 is adjusted depending upon theconditions of the floor 10, the amplitude of vibration of the floor 10can be minimized. In addition, the amplitude and frequency of thevibration transmitted from the frame 88 to the floor 10 change dependingupon the conditions of the EC mounter 14, e.g., the mass of the mounter14 itself, and the speed of movement of each of the X-axis and Y-axistables 28, 30 and the movable table 70. The mass of the movable ECsupplying device as a whole changes as the number of EC supplying units72 mounted on the movable table 70 changes and/or as the number of ECsstored in each of the EC supplying units 72 changes. The speed ofoperation of the EC mounter 14 changes. However, since thevibration-damping characteristic of each of the adjustable dampers 136is most appropriately adjustable, the vibration which is transmitted tothe floor 10 is more effectively reduced and any excessive vibration ofthe EC mounter 14 is most effectively prevented.

The load and vibrational force exerted to a first portion of the frame88 that supports the movable table 70 are greater than those exerted toa second portion of the frame 88 that is opposite to the first portionwith respect to the mounting device 18. However, the greater number ofspring units 92 (i.e., two) are provided between the first portion andthe floor surface 10 than the number of spring unit(s) 92 (i.e., one)provided between the second portion and the floor surface 10. Therefore,the frame 88 is kept horizontal, and the vibration of the frame 88produced by the movement of the movable table 70 is effectively damped.

Thus, the present EC-mounter supporting apparatus 12 can damp thevibration of the frame 88 relative to the floor surface 10, whilepermitting the frame 88 to move relative to the floor surface 10. Sincethe relative vibration of the frame 88 and the floor surface 10 isreduced by the adjustable dampers 136 of the supplying units 94 and theunadjustable dampers of the spring units 92, the vibration istransmitted as such to the floor 10.

The present EC-mounter supporting apparatus 12 permits the base member22 in the form of the frame 88 to move relative to the floor surface 10,and damps the relative vibration of the base member 22 and the floorsurface 10. More specifically described, the elastic deformation of thesprings 134 permits the base member 22 to move relative to the floorsurface 10, so that the vibration of the EC mounter 14 is prevented frombeing transmitted to the floor 10. If the base member 22 is disposeddirectly on the floor surface 10, the base member 22 and the floorsurface 10 would be vibrated as a unit and the floor surface 10 would belargely vibrated. According to the present invention, the base member 22is supported on the floor surface 10 via the springs 134. Accordingly,the vibration of the floor surface 10 is reduced, but the vibration ofthe base member 22 is increased. Moreover, the floor surface 10 mayresonate with the base member 22 and the vibration of the surface 10 maybe amplified. To solve this, the adjustable dampers 136 and theunadjustable dampers damp the vibration of the base member 22. Since thedampers are provided between the base member 22 and the floor surface10, a portion of the vibration of the base member 22 is damped by thedampers whereas another portion of the vibration is transmitted to thefloor surface 10 via the dampers. However, this portion is considerablysmaller than the vibration which would be transmitted to the floor 10 inthe case where neither the springs 134 nor the dampers 136 are provided.Thus, the vibration of the floor surface 10 is largely reduced, and thevibration of the base member 22 is prevented from lasting for a longtime, or being amplified because of resonance.

Thus, the amount of misalignment between the board holding device of thePCB supporting device 16 and the PCB carry-in or carry-out conveyor 46,48 when the holding device receives the PCB 32 from the carry-in device46 or when the holding device passes the PCB 32 to the carry-out device48, is negligibly small. Accordingly, the PCB 32 can be passed andreceived without any problems. More specifically described, after allthe ECs are mounted on the current PCB 32, the current PCB 32 is passedto the PCB carry-out conveyor 48, and a new PCB 32 is carried in ontothe board holding device. Concurrently with the carrying-out of thecurrent PCB 32 and/or the carrying-in of the new PCB 22, the movabletable 70 is returned to its EC-supply start position, which may producevibration. However, since this vibration is effectively reduced, theboard holding device is effectively prevented from being misaligned withthe PCB carry-in or carry-out conveyor 46, 48, so that the PCBs 32 canbe received and passed, without failure, among the board holding deviceand the carry-in and carry-out conveyors 46, 48.

The mounting device 18 takes an EC from the EC supplying device 20, inthe state in which the EC mounter 14 is being vibrated. However, afterpossible X-axis-direction and Y-axis-direction position errors androtation or angular position error of the EC held by the EC sucker arecorrected, the EC is mounted on the PCB 32. Thus, the position errors ofthe EC possibly resulting from the vibration are eliminated. Likewise,the EC is mounted on the PCB 32 in the state in which the EC mounter 14is being vibrated. However, experiments have proved that the accuracywith which the EC mounter 14 mounts the EC on the PCB 32 is comparableto that of a conventional EC mounter which is not used with the presentsupplying apparatus 12 but is used with a leveling sheet provided on thefloor surface 10 and a plurality of leveling bolts engaged with theleveling sheet.

In the present EC mounter 14, the respective movable portions (i.e., theX-axis table 28, the Y-axis table 30, the rotary plates 60, the movabletable 70, etc.) of the PCB supporting device 16, the mounting device 18,and the movable EC supplying device 20 are moved by the servomotors 34,76 as the drive sources. Since the frequency of vibration of the ECmounter 14 is much smaller than the frequency of response of theservomotors 34, 76, the servomotors 34, 76 are effectively responsive tothe vibration. More specifically described, when the base member 22 isvibrated, the PCB supporting device 16, the mounting device 18, and themovable EC supplying device 20 which are supported on the base member 22are vibrated with the base member 22, so that each of the movableportions (e.g., the X-axis table 28) of the devices 16, 18, 20 issubjected to an inertia force equal to the product of its mass and theacceleration of the vibration. This inertia force changes at the samefrequency (e.g., 10 Hz) as that of the vibration of the base member 22.Thus, the load exerted to the servomotor (e.g., the X-axis-table drivemotor 34) which drives the each movable portion changes at thatfrequency. However, the frequency of response of the servomotor 34 isabout 80 Hz much higher than 10 Hz, and accordingly the drive or outputtorque of the servomotor 34 increases and decreases as the load exertedthereto increases and decreases. Thus, each movable portion can beaccurately moved to a predetermined position. That is, the EC mounter 14is free from the problem that the accuracy of mounting of ECs is loweredbecause of the vibration of the base member 22.

The inclination adjusting device 90 can keep the frame 88 horizontal,i.e., parallel to the floor surface 10, even though the weight of themovable EC supplying device 20 as a whole may change. As describedpreviously, the height position of the dog 118 may be adjusted, when theEC mounter 14 is disposed, in the state in which no EC supplying units72 have been mounted on the movable table 70. Accordingly, if the ECsupplying units 72 are mounted on the movable table 70, the mass of themovable EC supplying device 20 increases, which leads to increasing theload exerted to the rear portion of the frame 88 that supports thesupplying device 20. Therefore, the respective compression coil springsof the two spring units 92 provided on both sides of the inclinationadjusting device 90 in the table-movement direction (i.e., the two units92 provided between the rear portion of the frame 88 and the floorsurface 10), half the respective compression coil springs 134 of the twosupporting units 94 that are provided on the side of the rear portion ofthe frame 88, and the air spring 96 are compressed. Thus, the pivotablelever 108 is pivoted toward the air-supply position (counterclockwise inFIG. 5) of the direction control valve 100, and eventually the controlvalve 100 is switched to the air-supply position. As a result, thepressurized air is supplied to the air spring 96 and the air pressure ofthe air spring 96 is increased. Since the elasticity of the air spring96 is increased, the rear portion of the frame 88 is raised. When theelasticity of the air spring 96 is increased by an amount correspondingto the increased amount of the mass of the EC supplying device 20, thepivotable lever 108 is returned to its initial horizontal posture, i.e.,its reference position. Thus, the supplying of the pressurized air tothe air spring 96 is stopped. In short, even though the load applied tothe rear portion of the frame 88 may be increased because of theincreased weight of the EC supplying device 20, the height of the airspring 96 is kept at a predetermined value, and the height position ofthe frame 88 from the floor surface 10 is kept at a predeterminedposition. Thus, the frame 88 is kept parallel to the floor surface 10.The total number of the EC supplying units mounted on the movable table70 varies depending upon, e.g., the sort of the PCB 32 in use. In eachcase, the frame 88 as the base member 22 is kept parallel to the floorsurface 10.

On the other hand, as the supplying of the ECs from the EC supplyingunits 72 to the mounting device 18 progresses, the number of the ECsheld by each of the supplying units 72 decreases, which leads todecreasing the weight of the movable EC supplying device 20. In thiscase, the rear portion of the frame 88 moves upward, which causes thepivotable lever 108 to be pivoted toward the air-relieve position of thedirection control valve 100 (clockwise in FIG. 5), thereby causing thecontrol valve 100 to be switched to the air-relieve position. Thus, thepressurized air is relieved from the air spring 96 into the atmosphere,and the air pressure of the air spring 96 is lowered. Therefore, theelasticity of the air spring 96 is decreased, and the rear portion ofthe frame 88 is lowered. When the elasticity of the air spring 96 isdecreased by an amount corresponding to the decreased amount of theweight of the EC supplying device 20, the pivotable lever 108 isreturned to its initial horizontal posture, i.e., its referenceposition. Thus, the relieving of the pressurized air from the air spring96 is stopped. In short, even though the load applied to the rearportion of the frame 88 may be decreased because of the decreased weightof the EC supplying device 20, the height of the air spring 96 is keptat the predetermined value, and the height position of the frame 88 fromthe floor surface 10 is kept at the predetermined position. Thus, theframe 88 is automatically kept parallel to the floor surface 10, thoughthe total number of the ECs or the total weight of the EC supplyingdevice 20 gradually decreases during the EC mounting operation.

Thus, the height of the air spring 96 is kept at the predeterminedvalue, though the load exerted to the rear portion of the frame 88changes. That is, the inclination of the frame 88 relative to the floorsurface 10 in the front-rear direction is adjusted, and the frame 88 iskept parallel to the floor surface 10. The direction control valve 100is provided by a valve which is automatically and mechanically switchedin response to the inclination of the frame 88 relative to the floorsurface 10. Since the control valve 100 is mechanically switched inresponse to the inclination of the frame 88, the valve 100 is opened byan amount corresponding to the amount of inclination of the frame 88.For example, in the state in which the frame 88 is inclined by a smallamount, the valve 100 is opened by a small amount, which allows a smallamount of air to be flown into, or out of, the air spring 96. Thus, theflow-direction control valve 100 also functions as a flow-amount controlvalve. Therefore, the inclination of the frame 88 is finely adjusted inthe automatic manner.

The EC-mounter supporting apparatus 12 shown in FIG. 2 includes just oneinclination adjusting device 90 to its advantage. However, FIG. 11 showsanother EC-mounter supporting apparatus 200 which includes twoinclination adjusting devices 90. The two adjusting devices 90 areprovided, between the floor surface 10 and a portion of the frame 88that supports the movable table 70, at respective locationscorresponding to opposite end portions of the table-movement area in thetable-movement direction. Each of the two adjusting devices 90 of thesupporting apparatus 200 is identical with the adjusting device 90 ofthe supporting apparatus 12, i.e., includes the air spring 96 and themechanical valve device 98. The two adjusting devices 90 of thesupporting apparatus 200 are identical with each other, and are arrangedsymmetrically with each other with respect to a plane which passesthrough the center of the frame 88 and is perpendicular to the plane ofthe frame 88 and to the lengthwise direction of the frame 88.

Since the two inclination adjusting devices 90 are provided atrespective positions distant from each other in a direction parallel tothe table-movement direction, the adjusting devices 90 cooperate witheach other to adjust, like the inclination adjusting device 90 of theEC-mounter adjusting apparatus 12, the inclination of the frame 88relative to the floor surface 10 in a direction perpendicular to thedirection in which the respective EC-supply portions of the EC supplyingunits 72 are arranged on the movable table 70. Thus, the frame 88 iskept parallel to the floor surface 10. Even though the balance ofrespective loads exerted to the supporting apparatus 200 from twoportions of the frame 88 that are distant from each other in thetable-movement direction may be broken as the movable table 70 is moved,the frame 88 can be kept parallel to the floor surface 10. Like thesingle adjusting device 90 of the supporting apparatus 12, each of thetwo adjusting devices 90 of the supporting apparatus 200 can be adjustedsuch that the direction control valve 100 of the each device 90 isswitched to adjust the air pressure of the air spring 96 and therebykeep the predetermined height of the air spring 96. Thus, the frame 88is kept parallel to the floor surface 10.

In the case where the floor surface 10 has a great undulation orinclination, the EC-mounter supporting apparatus 12 or 200 may bedisposed on the floor surface 10 via one or more level-adjust members(e.g., steel plates) having appropriate thicknesses. In this case,leveling bolts may be used to make a horizontal plane which supports thesupporting apparatus 12, 200 and the EC mounter 14.

According to the principle of the present invention, an EC-mountersupporting apparatus may include one or more elastic members and one ormore unadjustable dampers but may not include any adjustable dampers.For example, in the EC-mounter supporting apparatus 12, 200, the twosupporting units 94 may be replaced with additional two spring units 92.

Otherwise, the pilot-type variable shut-off valves 158, 160 may bereplaced with respective pilot-type shut-off valves each of which is notadjustable with respect to its valve opening or closing pressure, i.e.,has a predetermined valve opening or closing pressure.

The EC-mounter supporting apparatus 12, 200 may employ three or moreinclination adjusting devices 90. For example, it is possible that twoadjusting devices 90 be provided between the floor surface 10 and twoportions of the frame 88 that support the movable table 70 and aredistant from each other in the table-movement direction, and oneadjusting device 90 be provided between the floor surface 10 and aportion of the frame 88 that supports the PCB supporting device 16 andis opposite to the EC supplying device 20 with respect to the mountingdevice 18 in the front-rear direction. Otherwise, it is possible that inaddition to the two adjusting devices 90 provided between the floorsurface 10 and the two portions of the frame 88 that support the movabletable 70 and are distant from each other in the table-movementdirection, two more adjusting device 90 be provided between the floorsurface 10 and two portions of the frame 88 that support the PCBsupporting device 16 and are distant from each other in the direction inwhich the PCB 32 is conveyed by the PCB carry-in and carry-out devices46, 48, this direction being parallel to the table-movement direction.In the latter case, the four adjusting devices 90 in total are providedat respective positions corresponding to the four corners of the frame88. In each case, the inclination of the frame 88 relative to the floorsurface 10 is adjusted and the frame 88 is kept parallel to the floorsurface 10. In addition, the height position of the frame 88 or theEC-mounter 14 can be adjusted to a desirable value, and the degree ofhorizontality of the same 88, 14 is increased.

While the present invention has been described in its preferredembodiments, it is to be understood that the invention may be embodiedwith other changes, improvements, and modifications that may occur tothe person skilled in the art without departing from the scope andspirit of the invention defined in the appended claims.

What is claimed is:
 1. An apparatus for supporting an electric-componentmounter including a substrate supporting device which supports a circuitsubstrate, an electric-component supplying device which supplies aplurality of electric components to be mounted on the circuit substrate,a mounting device which receives the electric components from theelectric-component supplying device and mounts the electric componentson the circuit substrate supported by the substrate supporting device,and a base member which supports the substrate supporting device, theelectric-component supplying device, and the mounting device, theapparatus comprising:four elastic members each of which is for beingprovided between the base member and a surface of a floor which supportsthe base member; four dampers each of which is for damping vibration ofthe base member and the floor surface relative to each other, thevibration resulting from elastic deformation of the elastic member; twoelongate upper members each of which is for being fixed to the basemember; and two elongate lower members each of which is for beingprovided on the floor surface, two first elastic members of the fourelastic members and two first dampers of the four dampers being providedbetween a first elongate upper member of the two elongate upper membersand a first elongate lower member of the two elongate lower members, soas to provide a first supporting unit, two second elastic members of thefour elastic members and two second dampers of the four dampers beingprovided between a second elongate upper member of the two elongateupper members and a second elongate lower member of the two elongatelower members, so as to provide a second supporting unit, one of the twofirst elastic members of the first supporting unit being provided at oneof lengthwise opposite end portions of the first elongate upper memberand one of lengthwise opposite end portions of the first elongate lowermember, the other of the two first elastic members being provided at therespective other end portions of the first elongate upper and lowermembers, one of the two first dampers being provided at the respectiveone end portions of the first elongate upper and lower members, theother of the two first dampers being provided at the respective otherend portions of the first elongate upper and lower members, one of thetwo second elastic members of the second supporting unit being providedat one of lengthwise opposite end portions of the second elongate uppermember and one of lengthwise opposite end portions of the secondelongate lower member, the other of the two second elastic members beingprovided at the respective other end portions of the second elongateupper and lower members, one of the two second dampers being provided atthe respective one end portions of the second elongate upper and lowermembers, the other of the two second dampers being provided at therespective other end portions of the second elongate upper and lowermembers, wherein the first and second supporting units are forcooperating with each other to support the base member at respectivelocations which are distant from each other in horizontal direction. 2.An apparatus according to claim 1, for supporting the electric-componentmounter including the mounting device which receives, at a predeterminedcomponent-receive position, the electric components from theelectric-component supplying device, and including theelectric-component supplying device which comprises a movableelectric-component supplying device which includes a movable table whichis movable along a straight line passing through the component-receiveposition; and a plurality of component supplying units which areprovided on the movable table and each of which is selectivelypositioned at the component-receive position by the movement of themovable table, wherein the damper is for damping the relative vibrationof the base member and the floor surface in at least a directionparallel to the straight line.
 3. An apparatus according to claim 2,wherein the damper is for damping the relative vibration of the basemember and the floor surface in all directions on at least a verticalplane parallel to the straight line.
 4. An apparatus according to claim1, wherein the damper comprises an adjustable damper which has anadjustable vibration damping characteristic.
 5. An apparatus accordingto claim 1, wherein the damper comprises an unadjustable damper whichhas an unadjustable vibration damping characteristic.
 6. An apparatusaccording to claim 1, further comprising at least one inclinationadjusting device which is for being provided between the base member andthe floor surface and which is for adjusting an inclination of the basemember relative to the floor surface.
 7. An apparatus according to claim1, for supporting the electric-component mounter including theelectric-component supplying device which comprises a component-supplytable and a plurality of component supplying units which are provided onthe component-supply table such that respective component-supplyportions of the component supplying units are arranged along a straightline, wherein the apparatus further comprises an inclination adjustingdevice which is for being provided between the floor surface and aportion of the base member that supports the component-supply table, andwhich is for adjusting an inclination of the base member relative to thefloor surface.
 8. An apparatus according to claim 7, for supporting theelectric-component mounter including the mounting device which receivesthe electric components from the electric-component supplying device, ata predetermined component-receive position through which the straightline along which the respective component-supply portions of thecomponent supplying units are arranged passes, and including theelectric-component supplying device which comprises a movableelectric-component supplying device which comprises the component-supplytable comprising a movable table which is movable along the straightline, and the component supplying units having the respectivecomponent-supply portions each of which is selectively positioned at thecomponent-receive position by the movement of the movable table, whereinthe first and second supporting units are provided at the respectivelocations which are distant from each other in the horizontal directionparallel to the straight line, and each of the first and second dampersof the first and second supporting units is for damping the relativevibration of the base member and the floor surface in all directions onat least a vertical plane parallel to the straight line.
 9. An apparatusfor supporting an electric-component mounter including a substratesupporting device which supports a circuit substrate anelectric-component supplying device which supplies a plurality ofelectric components to be mounted on the circuit substrate, a mountingdevice which receives the electric components from theelectric-component supplying device and mounts the electric componentson the circuit substrate supported by the substrate supporting device,and a base member which supports the substrate supporting device, theelectric-component supplying device, and the mounting device theapparatus comprising:at least one elastic member which is for beingprovided between the base member and a surface of a floor which supportsthe base member; and at least one adjustable damper which has anadjustable vibration damping characteristic and which is for dampingvibration of the base member and the floor surface relative to eachother, the vibration resulting from elastic deformation of the elasticmember, wherein the adjustable damper comprises:a movable member whichis for being movable as a unit with the base member; a stationary memberwhich is for being substantially immovable relative to the floorsurface; a friction member which is held by one of the movable andstationary members such that the friction member is movable toward, andaway from, the other of the movable and stationary members and isfrictionally contactable with said other of the movable and stationarymembers; and a pressing device which is provided between the frictionmember and said one of the movable and stationary members and whichpresses, with an adjustable pressing force, the friction member againstsaid other of the movable and stationary members.
 10. An apparatusaccording to claim 9, wherein the pressing device comprises afluid-pressure-operated cylinder device which includes a cylinder and apiston and which is fixed to said one of the movable and stationarymembers, the piston pressing the friction member against said other ofthe movable and stationary members.
 11. An apparatus for supporting anelectric-component mounter including a substrate supporting device whichsupports a circuit substrate, an electric-component supplying devicewhich supplies a plurality of electric components to be mounted on thecircuit substrate, a mounting device which receives the electriccomponents from the electric-component supplying device and mounts theelectric components on the circuit substrate supported by the substratesupporting device, and a base member which supports the substratesupporting device, the electric-component supplying device, and themounting device, the apparatus comprising:at least one elastic memberwhich is for being provided between the base member and a surface of afloor which supports the base member; at least one damper which is fordamping vibration of the base member and the floor surface relative toeach other, the vibration resulting from elastic deformation of theelastic member; and at least one inclination adjusting device which isfor being provided between the base member and the floor surface andwhich is for adjusting an inclination of the base member relative to thefloor surface, wherein the inclination adjusting device comprises:a gasspring which comprises a gas chamber and a compressible gas enclosed inthe gas chamber; and a leveling valve device which adjusts a pressure ofthe compressible gas enclosed in the gas chamber of the gas spring andthereby adjusts the inclination of the base member relative to the floorsurface.
 12. An apparatus according to claim 11, wherein the levelingvalve device comprises a mechanical valve device which is for beingprovided between the base member and the floor surface and which is foradjusting the inclination of the base member relative to the floorsurface, based on movement of the base member and the floor surfacerelative to each other in a direction intersecting a horizontal plane.